The COVID‐19 epidemic Velavan, Thirumalaisamy P.; Meyer, Christian G.
TM & IH. Tropical medicine and international health/TM & IH. Tropical medicine & international health,
March 2020, Letnik:
25, Številka:
3
Journal Article
Pancreatic cancer has an extremely poor prognosis and prolonged survival is achieved only by resection with macroscopic tumor clearance. There is a strong rationale for a neoadjuvant approach, since ...a relevant percentage of pancreatic cancer patients present with non-metastatic but locally advanced disease and microscopic incomplete resections are common. The objective of the present analysis was to systematically review studies concerning the effects of neoadjuvant therapy on tumor response, toxicity, resection, and survival percentages in pancreatic cancer.
Trials were identified by searching MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials from 1966 to December 2009 as well as through reference lists of articles and proceedings of major meetings. Retrospective and prospective studies analyzing neoadjuvant radiochemotherapy, radiotherapy, or chemotherapy of pancreatic cancer patients, followed by re-staging, and surgical exploration/resection were included. Two reviewers independently extracted data and assessed study quality. Pooled relative risks and 95% confidence intervals were calculated using random-effects models. Primary outcome measures were proportions of tumor response categories and percentages of exploration and resection. A total of 111 studies (n = 4,394) including 56 phase I-II trials were analyzed. A median of 31 (interquartile range IQR 19-46) patients per study were included. Studies were subdivided into surveys considering initially resectable tumors (group 1) and initially non-resectable (borderline resectable/unresectable) tumors (group 2). Neoadjuvant chemotherapy was given in 96.4% of the studies with the main agents gemcitabine, 5-FU (and oral analogues), mitomycin C, and platinum compounds. Neoadjuvant radiotherapy was applied in 93.7% of the studies with doses ranging from 24 to 63 Gy. Averaged complete/partial response probabilities were 3.6% (95% CI 2%-5.5%)/30.6% (95% CI 20.7%-41.4%) and 4.8% (95% CI 3.5%-6.4%)/30.2% (95% CI 24.5%-36.3%) for groups 1 and 2, respectively; whereas progressive disease fraction was estimated to 20.9% (95% CI 16.9%-25.3%) and 20.8% (95% CI 14.5%-27.8%). In group 1, resectability was estimated to 73.6% (95% CI 65.9%-80.6%) compared to 33.2% (95% CI 25.8%-41.1%) in group 2. Higher resection-associated morbidity and mortality rates were observed in group 2 versus group 1 (26.7%, 95% CI 20.7%-33.3% versus 39.1%, 95% CI 29.5%-49.1%; and 3.9%, 95% CI 2.2%-6% versus 7.1%, 95% CI 5.1%-9.5%). Combination chemotherapies resulted in higher estimated response and resection probabilities for patients with initially non-resectable tumors ("non-resectable tumor patients") compared to monotherapy. Estimated median survival following resection was 23.3 (range 12-54) mo for group 1 and 20.5 (range 9-62) mo for group 2 patients.
In patients with initially resectable tumors ("resectable tumor patients"), resection frequencies and survival after neoadjuvant therapy are similar to those of patients with primarily resected tumors and adjuvant therapy. Approximately one-third of initially staged non-resectable tumor patients would be expected to have resectable tumors following neoadjuvant therapy, with comparable survival as initially resectable tumor patients. Thus, patients with locally non-resectable tumors should be included in neoadjuvant protocols and subsequently re-evaluated for resection.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The degradation mechanisms of natural fiber in the alkaline and mineral-rich environment of cement matrix are investigated. Cement hydration is presented to be a crucial factor in understanding fiber ...degradation behavior by designing a contrast test to embed sisal fibers in pure and metakaolin modified cement matrices. In addition to durability of sisal fiber-reinforced cement composites determined by means of flexural properties, degradation degree of the embedded fibers is directly evaluated by proposing a novel separation approach. The results indicate that, by reducing alkalinity of pore solution, metakaolin effectively mitigates the deterioration of natural fiber. By combining results of thermogravimetric analysis and microstructure, the alkali degradation process of natural fiber, which consists of hydrolysis of lignin and hemicellulose, stripping of cellulose microfibrils and deterioration of amorphous regions in cellulose chains, is visually presented. Two new concepts of mineralization mechanism, calcium hydroxide (CH)-mineralization and self-mineralization, are also proposed and quantitatively characterized.
The text reconstructs the concepts of practice and practicality used in ethnomethodology and conversation analysis and examines their internal similarities and differences as well as similarities and ...differences to other practice theories. After a description of the characteristics of practice theories, the ethnomethodological perspective on practice and practicality is presented. Then, the use of the terms in conversation analysis is examined. Ethnomethodology uses the notions of “practice” and “practicality” to outline a non-metaphysical theory of social order in which the sharedness of rules or meanings is not presupposed. “Practical” here means that social action, and social order more generally, are practically grounded as well as temporally and situationally constrained. The fact that practical action is fundamentally situated and can only be understood “from within” establishes an essentially indexical character of practical action. In conversation analysis, “practices” are viewed as “context-free” but “context-sensitive” components that constitute action and as such become the objects of investigation. While some have diagnosed a departure of conversation analysis from its ethnomethodological roots, I argue that “context-freeness” and “context-sensitivity” should be complemented by “context-productivity” by reference to Garfinkel’s interpretation of Aron Gurwitsch’s gestalt phenomenology in order to formulate a more encompassing concept of practice.
Monkeypox 2022 outbreak: An update Velavan, Thirumalaisamy P.; Meyer, Christian G.
Tropical medicine & international health,
July 2022, 2022-07-00, 20220701, Letnik:
27, Številka:
7
Journal Article
•Characteristics of asymptomatic and presymptomatic infection are not identical.•Younger age correlates strongly with asymptomatic and mild infections.•Asymptomatic infections do not provide clear ...guidance for public-health measures.•Asymptomatic cases should be reported in official COVID-19 statistics.•Asymptomatic individuals carrying SARS-CoV-2 are hidden drivers of the pandemic.
While successful containment measures of COVID-19 in China and many European countries have led to flattened curves, case numbers are rising dramatically in other countries, with the emergence of a second wave expected. Asymptomatic individuals carrying SARS-CoV-2 are hidden drivers of the pandemic, and infectivity studies confirm the existence of transmission by asymptomatic individuals. The data addressed here show that characteristics of asymptomatic and presymptomatic infection are not identical. Younger age correlates strongly with asymptomatic and mild infections and children as hidden drivers. The estimated proportion of asymptomatic infections ranges from 18% to 81%. The current perception of asymptomatic infections does not provide clear guidance for public-health measures. Asymptomatic infections will be a key contributor in the spread of COVID-19. Asymptomatic cases should be reported in official COVID-19 statistics.
•Recycled fine aggregates with saturation degrees of 0%, 50% and 100% were studied.•Effect of internal curing on recycled aggregate concrete was evaluated.•RCA had properties comparable to that of ...virgin aggregate due to internal curing.
In this study, the suitability of replacing the virgin aggregate with recycled concrete aggregate (RCA) was examined under the hypothesis that the higher porosity and water absorption capacity of RCA would provide the natural moisture reservoir needed for internal curing. The concrete’s workability, compressive and split tensile strength and freeze–thaw cycle resistance and shrinkage was determined for RCA with 0%, 50% and 100% saturation. The strength increased with the saturation degree and decreased with for larger water/cement ratios and RCA contents. Using saturated or semi-saturated RCA in the concrete positively affected the durability via internal curing.
A new ichnospecies of a large theropod dinosaur, Megalosauripus transjuranicus, is described from the Reuchenette Formation (Early-Late Kimmeridgian, Late Jurassic) of NW Switzerland. It is based on ...very well-preserved and morphologically-distinct tracks (impressions) and several trackways, including different preservational types from different tracksites and horizons. All trackways were excavated along federal Highway A16 near Courtedoux (Canton Jura) and systematically documented in the field including orthophotos and laserscans. The best-preserved tracks were recovered and additional tracks were casted. Megalosauripus transjuranicus is characterized by tridactyl tracks with clear claw and digital pad impressions, and notably an exceptionally large and round first phalangeal pad on the fourth digit (PIV1) that is connected to digit IV and forms the round heel area. Due to this combination of features, M. transjuranicus clearly is of theropod (and not ornithopod) origin. M. transjuranicus is compared to other Megalosauripus tracks and similar ichnotaxa and other unassigned tracks from the Early Jurassic to Early Cretaceous. It is clearly different from other ichnogenera assigned to large theropods such as Eubrontes-Grallator from the Late Triassic and Early Jurassic or Megalosauripus-Megalosauropus-Bueckeburgichnus and Therangospodus tracks from the Late Jurassic and Early Cretaceous. A second tridactyl morphotype (called Morphotype II) is different from Megalosauripus transjuranicus in being subsymmetric, longer than wide (sometimes almost as wide as long), with blunt toe impressions and no evidence for discrete phalangeal pad and claw marks. Some Morphotype II tracks are found in trackways that are assigned to M. transjuranicus, to M.? transjuranicus or M. cf. transjuranicus indicating that some Morphotype II tracks are intra-trackway preservational variants of a morphological continuum of Megalosauripus transjuranicus. On the other hand, several up to 40 steps long trackways very consistently present Morphotype II features (notably blunt digits) and do not exhibit any of the features that are typical for Megalosauripus (notably phalangeal pads). Therefore, it is not very likely that these tracks are preservational variants of Megalosauripus transjuranicus or Megalosauripus isp. These trackways are interpreted to have been left by an ornithopod dinosaur. The high frequency of large theropod tracks in tidal-flat deposits of the Jura carbonate platform, associated on single ichnoassemblages with minute to medium-sized tridactyl and tiny to large sauropod tracks has important implications for the dinosaur community and for paleoenvironmental and paleogeographical reconstructions. As with most other known occurrences of Megalosauripus tracks, M. transjuranicus is found in coastal settings, which may reflect the preference of their theropod trackmakers for expanded carbonate flats where food was abundant.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Renewable fuels contribute to net zero emissions by replacing fossil fuels in the transportation sector. Nevertheless, there are significant environmental concerns associated with renewable energy ...development, including land and water usage. This research explores the use of land and water related to large-scale renewable fuel production. We develop a multi-objective mathematical model to determine the optimal supply chain design for the EU's future renewable fuel demand in the transportation sector. We propose a flexible, multi-period, and multi-stage supply chain design that can accommodate multiple feedstocks and multiple products and that takes the seasonality of the resources into account. We consider economic and environmental impacts by minimizing total system costs, land use, and water use. Based on the analysis of the results, we gain insights into conflicting objective functions and the associated trade-offs and synergies to assist decision-makers in selecting an appropriate framework and gaining a better understanding of future opportunities and impacts of renewable fuel production. The outcome demonstrates that, despite not being a desirable alternative in terms of water and land usage, the utilization of energy crops as raw material has economic benefits. As shown by the results, the burden of such a supply chain lies with renewable electricity requirements that could be the capacity bottleneck and require investments. We find that we could achieve a nearly optimal value of land use and water use by increasing total cost by only 10%.
•A mathematical model for multi-objective optimization of renewable fuel supply chain with economic and environmental criteria•A flexible, multi-period, and multi-stage supply chain design•Considering multiple feedstocks, multiple products, and the seasonality of the resources•Achieving a three-dimensional Pareto frontier and tradeoffs between pairs of objective functions•European-wide case study is resolved using the proposed model
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